Watertight watch case with oval crystal



Dec. 8, 1970 1.. FISCHER 3,545,197

WATERTIGHT WATCH CASE WITH OVAL CRYSTAL Filed July 5, 1968 III/111 o "f'Z' H mm M J 24 A? j/ZZ L I FIG. 3

ATTORNEY United States Patent 3,545,197 WATERTIGHT WATCH CASE WITH OVAL CRYSTAL Ludwig Fischer, Waterbury, Conn., assignor to Benrus Corporation, a corporation of Delaware Filed July 5, 1968, Ser. No. 742,768 Int. Cl. G04b 37/08 US. Cl. 58-90 13 Claims ABSTRACT OF THE DISCLOSURE A watertight watch case comprises a non-circular crystal having a groove formed in its peripheral surface. A bezel has an inwardly and upwardly sloping bezel surface of a size and shape generally corresponding to the non-circular peripheral surface of the crystal and a deformable sealing element, received in the crystal surface groove, is compressed between the crystal and bezel surface, thereby to retain the crystal and the bezel in substantially watertight engagement.

The present invention relates to watch cases, and particularly to a watertight watch case in which the crystal peripheral surface is non-circular in shape.

In many watches the crystal and dial are non-circular in peripheral shape. Specifically it is often desired to design the crystal in oval form, the longer axis of the oval crystal usually extending along the width of the wearers wrist. It has also become common and desirable in the construction of wrist watches to secure the crystal and its supporting bezel in a watertight manner so that the watch mechanism will not be damaged when the watch is exposed to moisture or dust particles.

In the construction of watches having circular crystals and bezels, the watertight engagement between crystal and bezel is effected by precisely machining and forming the mating circumferential surfaces of the crystal and the bezel and causing the crystal to resiliently expand into engagement with the bezel, thereby to insure that when the crystal is inserted in the bezel the resulting engagement between the bezel surface and the crystal will be watertight.

However, in the construction of watch pieces having non-circular crystals as in watches in which the crystal is oval shaped, it is especially diflicult toobtain the required precise machining of the crystal and bezel peripheral surfaces required to obtain the desired watertight engagement. This difiiculty in machining is particularly troublesome in the forming of the crystal surface. Unless the crystal and bezel surfaces mate very accurately all around the bezel, the expansion of the crystal will leave some spaces unsealed, and the existence of even one such space is fatal to the maintenance of adequate watertightness.

As a result of this diificulty in forming the mating crystal and bezel surfaces for non-circular shaped crystals, the construction of watertight watch pieces of this type has been, until now, a difiicult and expensive procedure, requiring the use of special and costly equipment.

It is, therefore, an object of the present invention to provide a watertight watch case having a decorative noncircular crystal, in which the difiiculties and disadvantages of the known constructions have been largely overcome.

It is a further object of the present invention to provide a watertight watch case in which the crystal is substantially oval in shape.

Another object of the present invention is to provide a watch case having a non-circular crystal in which a reduced degree of precision in crystal forming is required, thus making low cost well within the scope of available production facilities, and which achieves the desired watertight seal by the use of a relatively few inexpensive components.

It is an additional object of the present invention to provide a watertight watch case having a non-circular shaped crystal surface in which a reliable, long-lasting and effective water tight seal is obtained in a relatively simple and inexpensive manner.

In accordance with the present invention, a watch crystal having a non-circular peripheral surface has an annular groove formed in that surface which extends along the entire periphery thereof. The bezel has an inwardly and upwardly sloping bezel surface which defines a crystal receiving opening of a size and shape generally corresponding to that of the crystal surface. A sealing element is seated in and extends out from the groove in the crystal surface and is compressed between the bezel surface and the crystal so as to elfectively retain the crystal and bezel in a substantially watertight manner.

Preferably, the area along which the sealing element contacts the bezel surface is spaced below the upper end of the bezel surface, the height of that contact area being of substantial extent, many times greater than a line contact and preferably at least about one-half the height of the sealing element itself. The extent to which the bezel surface slopes is greater than that of the slope of the crystal surface. As a result of this construction, the sloping bezel surface is effective to retain the sealing element in place and thus to retain the crystal in secure, reliable and watertight engagement with the bezel for an indefinite period.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to the construction of a watertight watch case as defined in the accompanying claims and as described in this specification, taken together with the accompanying drawing in which:

FIG. 1 is a top plan view of a non-circular, watertight watch case according to the present invention;

FIG. 2 is a fragmentary vertical section taken along the line 2-2 of FIG. 1; and

FIG. 3 is an exploded side elevational view, partially broken away and cross-sectioned, showing the various components of the watch case of FIG. 1.

The watertight watch case 10 of the present invention comprises a transparent crystal 12 of suitable plastic material which is stifily elastic. Crystal 12 is inserted into a crystal receiving opening defined by an inwardly and upwardly sloping bezel surface 14 formed in a watch case body 16. As seen best in FIG. 1, the crystal 12 is noncircular in shape and, as here specifically shown, is substantially oval, that is, the annular peripheral depending flange 18 of crystal 12 defines an oval surface. An annu lar groove 20 extends along the entire periphery of flange 18 and receives therein a portion of a sealing element here shown as a deformable elastomeric ring 22, the remaining portion of ring 22 extending radially beyond groove 20.

To assemble the components shown in FIG. 3 to form the completed watertight watch case 10, the sealing element 22 is placed within groove 20 and the upper end 19 of the crystal peripheral flange 18 is grasped by an appropriate crystal applicator tool such as that disclosed in my co-pending application Ser. No. 742,769 entitled Crystal Applicator, assigned to the assignee of the present invention, and filed of even date herewith. The tool is effective to compress end .19 so as to slightly inwardly urge the crystal flange 18 until crystal 12 is able to fit completely within the opening defined by bezel surface 14 at which time the compression on end 19 is released. Then the lower end of the crystal peripheral flange 18, that is, the portion of flange 18 comprising groove 20 carrying sealing ring 22, moves radially outwardly towards engagement with bezel surface 14. This causes the portion of ring 22 extending beyond groove to engage bezel surface 14 and to be compressed between the crystal and the bezel surface to a substantial extent.

As shown best in FIG. 2, when sealing ring 22 is compressed between bezel surface 14 and flange 18 of crystal 12, the portion of sealing ring 22 lying within groove 20 substantially completely fills the groove. When the sealing ring 22 is thus compressed and flattened between crystal 12 and bezel surface 14, ring 22 engages the bezel sur face along an annular sloping contacting surface extending around the entire periphery of bezel surface 14. This contacting area is of an appreciable vertical height much greater than a line contact and may vary from at least one-half the normal vertical dimension (diameter) of sealing ring 22 to a full diameter of the ring 22. Ideally the vertical height of the contacting area approaches the diameter of the ring 22 which, in a typical embodiment, may be .030 inch. The height of the groove 20 is preferably substantially equal to or slightly less than the ring diameter, and the radial depth of the groove is preferably slightly greater than the ring radius. Moreover, that contacting surface preferably is spaced appreciably below the upper end or lip 24 of bezel surface 14. It is also to be noted that crystal flange .18, carrying the groove 20, is also sloped inwardly and upwardly, but to a noticeably lesser degree than the slope of bezel surface 14. In this manner the clearance between crystal 12 and bezel surface 14 is at a minimum at lip 24 so that ring 22 is compressed to the greatest extent along that portion of the contact surface nearest upper lip 24. Thus, in the event that crystal 12 should be forced upwardly, ring 22 will move up therewith and will be increasingly compressed by bezel surface 14. Hence crystal 12 is very reliably retained in bezel 16.

The angle of groove 20 formed in crystal 12 is substantially perpendicular to the sloping outer surface of flange 18. (FIG. 2.) As a consequence, substantially uniform pressure is applied to the upper and lower portions of the compressed ring 22 within groove 20, thereby to further retain ring 22 within groove 20.

Watch case body 16 also comprises an annular shoulder 26 which supports a flange 28 of a conventional watch mechanism 30, an oval shaped dial 32 being placed over mechanism so that the conventional minute and hour hands 34 and 36, operatively connected to mechanism 30, travel over indicia provided on dial 30 in a Well known manner. An annular groove 38 formed in body 16 receives an annular lip 40 of a resilient back cover 42 so as to retain cover 42 in place on watch case body 16.

Thus, a watertight watch case has been disclosed in which the crystal surface and the dial are of a decorative, non-circular shape. An effective watertight seal between the crystal and its mating bezel surface is produced in a relatively simple and economical manner, and yet that seal is reliable and capable of maintaining its watertightness for any foreseeable environmental conditions. In addition, an improved degree of crystal retention is obtained. Manufacturing irregularities in the shaping of the crystal and bezel surfaces may occur without destroyin g the desired watertight seal.

It will be further understood that the details of the single embodiment of the invention here specially disclosed can be widely varied, all without departing from the present invention as defined in the following claims:

I claim:

1. A watertight watch case comprising a crystal having a non-circular peripheral surface and an annular groove formed therein and extending about the entire periphery thereof, a bezel having an inwardly and upwardly sloping bezel surface defining a crystal-receiving opening of a size and shape substantially corresponding to that of said crystal surface, and a deformable sealing element received in and extending beyond said groove and engaging and compressed between said crystal and said bezel surface, thereby to retain said crystal in said bezel in a substantially watertight manner, said bezel and crystal surfaces constituting the portions of said bezel and crystal respectively which make the closest retaining approach to one another, said sealing element thereby constituting substantially the sole instrumentality retaining said crystal in said bezel.

2. The watch case of claim 1, in which both said crystal surface and said bezel surface are shaped substantially in the form of an oval.

3. The watch case of claim 1, in which said groove is formed in said crystal and extends perpendicular to the peripheral surface thereof.

4. The watch case of claim 1, in which said sealing element engages said bezel surface over a contact area spaced appreciably below the upper end of said bezel surface, whereby said bezel surface extends radially inwardly over said sealing element and hence effectively retains said crystal in position within said bezel.

5. The watch case of claim 4, in which said contact area has an appreciable vertical depth.

6. The watch case of claim 5, in which the depth of said contact area is equal to at least one-half the height of said sealing element.

7. The watch case of claim 6, in which both said crystal surface and said bezel surface are shaped substantially in the form of an oval.

8. The watch case of claim 1, in which said crystal surface slopes in the same direction, but to a lesser degree than, said bezel surface.

9. The watch case of claim 8, in which said groove is formed in said crystal and extends substantially perpendicular to the peripheral surface thereof.

10. The watch case of claim 8, in which said sealing element engages said bezel surface over a contact area spaced appreciably below the upper end of said bezel surface, whereby said bezel surface extends radially inwardly over said sealing element and hence effectively retains said crystal in position within said bezel.

11. The watch case of claim 10, in which said contact area has an appreciable vertical depth.

12. The watch case of claim 11, in which the depth of said contact area is equal to at least one-half the height of said sealing element.

13. The watch case of claim 12, in which both said crystal surface and said bezel surface are shaped substantially in the form of an oval.

References Cited UNITED STATES PATENTS 1,308,690 7/1919 Wachter 58-91 FOREIGN PATENTS 250,112 8/ 1947 Switzerland 58-9OA 256,883 9/1948 Switzerland 5 890A 393,197 5/1965 Switzerland 58-90 RICHARD B. WILKINSON, Primary Examiner G. H. MILLER, 1a., Assistant Examiner 

